Off the clock

[Mark 1]

QNH that is.

Not flying, but setting up an instrument panel and the altimeter was off the scale with the current pressure setting - 1037 HPa. The sub-scale stopped at 1035 though it did allow further adjustment beyond that.

This is a new certified sensitive altimeter with JAR form 1 (Winter).

I can't recall ever being off the top of the scale before and checking an old altimeter, the subscale on that goes up to 1050.

Does anyone know typically how often we get this high a pressure in the UK?

Is it common to have this limited a sub-scale?

[David Roberts]

I remember a few years ago seeing 1045 in the UK. Can't quite remember when though. It caused quite a 'stir' at the time, for the same reason.

[Fitter2]

If it has a JAA Form 1 it isn't new. Sure you don't mean an EASA Form 1?

Yes, I recall QNHs over 1040 a few times in the past 20 years, but it is unusual.

[Gulfstreamaviator]

Had 1045 last week.

Rather cold too..... but only -20c.


Brings up another question, the temperate correction for alt in cold...what about abnormal high px....

I am looking thru all my data but can not find an answer.????

glf

[Chilli Monster]

Get shot of it.

We've had high pressure in the UK above 1035 quite a bit this year. Most altimeters that I've come across go up to 1050 which should be suficient.

Whoever sold it to you has sold you something "not fit for use" and should be talked to about exchanging it.

[LH2]

I have a vague recollection from my ATPLs that there were two altimeter standards, the one that goes up to 1050 and the one that goes up to 1035-ish or so. I also seem to remember the scale is shorter on the low pressure side as well on the latter.

What I can't remember is where these two standards come from. Someone with better memory please enlighten us.

[Mark 1]

It's a Winter model 4550 and goes from 935 to 1035. I wanted a 57mm one for a small standby panel with an EFIS providing the primary flight display. There isn't much choice for 57mm altimeters unless you have a deep wallet.

Winter supply a lot of glider kit, so it's probably biased to being able to set zero at field altitude. As the EFIS will be the prime instrument for practical purposes, I'll settle for what I've got.

[Jumbo Driver]

... I'll settle for what I've got.

You'd better remind yourself how to use QNE, then ...

JD
;)

[C-dog]

Few today with QNH 1041. Seemed to be plenty more adjustment on the clock (forgot to see how far up it went despite already reading this thread)

1043 on Boxing Day, again no problems.

Flew many years ago on QNH 945 and the scale only went down to 950. Biggest worry was where was the wind going to come from - appeared to be in the eye of something.